Transmitter for telephone and other sound-transmitting instruments.



W. P. STUNZ.

TRANSMITTER FOR. TELEPHONE AND OTHER SOUND TRANSMITTING'INSTRUM ENTS;

APPLICATION HLED 050.31. 1910.

' 1,144,391- Patented June 29, 1915.

' 2 SHEETSSHEET n,

w. P. STUNZ. TRANSMITTER.FOR TELEPHONE AND OTHER SGUND TRANSMITTING INSTRUMENTS- I APPLICATION FILED DEC. 3h I9IO.

1,1%,391 Patented Julie 29, 1915.

2 SHEET a'-SIIEET 2.

' ETE WILLIAM PRESTON STUNZ, on LANsno'wNn, MARYLA D, ASSIGNOR, BY nnsnn ASSIGNMENTS, o THE WEBB TION on nnnawann TAIiKING ricrun'ns cclviranr, a. conrons- TnANsMITTEn iron TELEPHONE AND OTHER SO'UND-TRANSMITTIN INSTRUMENTS.

wisest,

specification of Letters Patent.

Patented June 29, 11915.

Application filed Deccinb'cr 31, 1910. Serial Noi 600,358.

To all wlz am it may concern: 7

Be it known that I, Wipnnuh PnnsToN STUNZ, a citizen of the United States, re-

siding at Lansdowne, in the county. of Balti more and State of Maryland, have invented certain new and useful Improvements in Transmitters for Telephone and other Sound-Transmitting Instruments; and I do declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to makeand use the same, reference being had to the accompanying drawings, and to the letters and figures of ref-- erence marked thereon, which form a part of this specification.

My invention relates to transmitters for telephone and other sound transmitting instruments; and it has primarily for its object to produce a transn'iitter in which the wave vibrations will be received and transmitted with exceptionally well-defined sharpness, clearncss and distinctness, and in which also will be obviated the necessity of dampers for the diaphragm of the instrument, and in which also will be embodied structural features calculated to simplify and otherwise improve the construction with the view of producing a transmitter possessing all of the desirable features while at the same time free from the presence of undesin able features and possessing the highest eiih ciency in the transmission of voice or other wave vibrations.

To the accomplishment of the foregoing and such other objects as may be made herethe mouth-piece omitted, on an enlarged scale; Fig. the casing of the'instrument, on an enlarged'scale; "Fig. 6 a rear end vie of the instrument, with the covering plates rea detail view of a portion of moved; Fig. 7 a rear face view of the diaphragm, showing also the clips or plates and conductors by which the diaphragm rods are connected to binding posts; Fig. 8 is a section through the diaphragm, showing also its rods, the insulating covering of one of the rods being in section, the view being on an enlarged scale; Fig. -9 is a diagrammatic view of the'diaphragm and electrodes, show ing the preferred manner of connecting the electrodes-in circuit; Fig. 10 is a diagrammatic view of the circuit ofFig. 9; Fig. 11 is a diagrammatic View of the diaphragm and electrodes illustrating a modified form of circuit; and Fig. 12 is a diagrammatic view of the circuitembodied in the construction illustrated in Fig. 11.

In the drawings the numeral 1 indicates the face-casing of the instrument formed with a threaded portion 2 to receive the mouth piece 3 and with an internally threaded and chambered portion 4 to receive the diaphragm 5 which will rest upon a shoulder or seat 6 formed for it in the chamber 4-, and will be held therein by a disk 7 having threaded engagement with the Walls of the chamber 4 and which may be held against movement by screws 8 as illustrated clearly in Fig. 4 of the drawing. Upon the disk 7 is mounted a block 9 made preferably of hard rubber and formed with chambers 10 and 11 to receive granular carbon. The block 9 is recessed next to the disk 7 so as to receive two carbon electrodes 12, 12*, one for each granular carbon chamber, said electrodes being separated from the disk 7 by a strip 15 of suitable insulating material which also extends between the disk and the block 9. The outer face of the block 9 is recessed so as to receive two carbon electrodes 14, 14*, one for each of the granular carbon chambers, and within the granular carbon chambers are movable carbon electrodes 13, 13, one for each chamber, and which are connected by rods 16, 16, to the diaphragm 5, these rods passing through appropriate openings made in the electrodes 12, 12* and the disk 7 for the purpose of being secured to the electrodes 13, 13 respectively by nuts 17, 17 and to the diaphragm by nuts 18, 18, insulated from the diainsulations 19,19", and the rods are held in place by plates 21, 21' through which and the block 9 and into the disk 7 though it may.

the electrodes 14, 14 and simultaneously pass screws 22 forsecuring said several parts together. This forms a very simple construction by which the several partsmay be readily assembled and also disassociated when desirable.

The outer edge of the diaphragm 5 1s inclosed by a resilient cushion 23 Wl'llCll may be and preferahgy is made of rubber, al-

' e made of other suitable elastic material; and strips 24, 24, of suitable insulating'material, are interposed-be tween the cushion 23' and the face-casing 1 and disk 7 respectively. By connecting the diaphragm 5 to themovable electrodes 13, 13". by the rods 16, 16 both of said electrodes arecaused to move with the diaphragm 5; and by having the outer edge of the diaphragm' 5 inclosed in a resilient cushion 23 interposed between the disk 7 and face-casing 1, the whole diaphragm will move back and forth under the influence of wave vibrations and this back and forth movement will be simultaneously imparted to the two movable electrodes 13, 13 so that the granular carbon between those electrodes and the electrodes 14, 14 will be compressed in the movement of the electrodes 18,-'13 toward pressure on the carbon granules between the electrodes 13--12 and the electrodes 13 12 will be proportionately released while lin the opposite movement of the electrodes 13, 13 the granular garbon betweenjthem and the electrodes 12, .12 will be compressed .supported to move back and forth under vibrations without flexure it follows that the electrodes connected thereto will move back and forth therewith to an equal extent one with the other and. consequently the action on the granular carbon in both chambers is the sameas to compressing the granules on one side of the two movable electrodes and releasing the pressure proportionately on the granules on the opposite sides of saidelectrodes in movement of the electrodes and the" diaphragm back and forth. In order that the diaphragm may possess the minimum of weight or lightness and at the same time have sufficient rigidity or sti'fl'ness to avoid flexure it is made preterably of aluminum and the necessary stiffness is given to it, by forming it with corrugations, flutes or ribs 29. By connecting each electrode with the diaphragm so that the to and fro movements of the diaphragm electrodes, each electrode is given the same extent of movement and without torsional strain on the several electrodes, and this makes possible the production of the two independent balanced circuits so as to fully utilize the entire product of a'simultaneous unbalancing in each. granular carbon chamber'.

In the preferred form of the invention, as illustrated in Fig 9 of the drawing, the rod 16 is connected by conductor 25 and a clip 26 to a binding post 27 designed to receive the wire which leads to a receiver,

and the rod-16 is connected by a conductor 25 and clip 26 to abinding post battery. In thisform-of the invention the electrode 14 will be connected by a wire or conductor 30 to the electrode 12, and the electrode 12 will be connected by a wire or conductor 30* with the electrode 14 so that the circuit will include the Wheatstone bridge principle. Under this construction when the diaphragm -5 is moved inwardly and the electrodes 13, 13 moved toward the electrodes 14, 14 the granular carbon between said electrodes is compressed so'as to create a low potential at the junction point of the Wheatstone bridge and the current will-flow from the source of electrical energy, for instance, from one pole of the battery through the conductor 28 to the rod 16 thence througlrthe conductor 25 to the receiver and return by way of the other conductor 25 of the receiver to the rod 16 and thence by way of. the conductor 28 to the source of energy or the other pole oft-he bat tery, thus completing the circuit. movement of the diaphragm in the opposite Upon direction the granular carbon between the electrodes 13-14 and the electrodes 13 14 Wlll be loosened and the granular carbon between the electrodes 12-13 and 12 13 will be compressed so that the current will flow from the source of energy or battery in the opposite direction to that previously described and consequently through the new low resistance transmitters formed by the electrodes 1213 and 121E and the com- 1 13 are at rest they are in; their neutral or 15 potentials o the-several electrodes are alike,

but when the electrodes 13-13 are moved no-voltage I o sition and atsuch time the in one direction or the other differences in potential areset up by reason of the changes 1n resistance of the granular carbon in-the hambers and thus analternating current is created. v a

- In Figs. 11 and 12 of the drawin there is 1; illustrated a different circuit'from t at illustrated in Figs. 9 and 10 of the drawing, due

to the employment of condensers in the circuit and the manner of connecting the electrodes as illustrated in Fig.11 In this'form the same designating characters are employed for the parts which correspond to like parts in Fig. 9, and additional deslgnating characters employed for the other parts.

In the form illustrated in Figs. 11 and 12 the electrodes of one trmsmitter chamber are connected straight or in'multiple with the electrodes of the other transmitter chamber, that is to say the electrode 12 is connected by the conductor 31 with the electrode '12; the electrode 14 is connected by the conductor 31 with the electrode 14; and

the electrode13 is connected with the electrode 13 by the conductor 32 joining the rod 160i the electrode 13 with the rod 16 of the electrode 13. A wire or conductor 28 leads from the conductor 14 to the battery or other source of energy the same asdescribed for the Wheatstone form of the invention illustrated in Fig. 9, and in the wire or conductor 28 which leads from the electrode 12*to the battery or source of electrical energy there is included the condensers 33 as illustrated in Fig. 12 of the drawing. In

this form of the invention the currentflows in the same direction in each transmitterchamber and causes both transmitter chambers to work as one, and when the electrodes 13. and 13 are at rest they are in a no-voltag'e or neutral position as they are both connect ed together, andwhen in operation the alternating or voice current terminals are in the path of the conductor leading from the electrodes 13-43 to the receiver and in the path of the current passing through the conductor having the condensers 33. With this description taken in connection with the diagrammatic illustration of the circuit .given in-Fig. 12 of the drawing the circuit W111 clear to the skilled in the art. c

In both forms of the invention-the arrangement of the electrodes in each transmitter chamber in relation to each other and to the diaphragm and the construction of the various parts are the same with-the exception of the difference in the manner of Iconnecting electrodes of one of the chambers.

with the electrodes of the other chamber,

and in both forms of the invention the features wliich are in common to both embed will be observed that by forming'each transmitterchamber with a movable electrode interposed between two other electrodes wlth granular carbon between the movable electrodes and the other electrodes of'the chambers, and connecting the movable electrodes of the two chambers with the diaphragm; there is formed a transmitter in whichthe granular carbon is compressed in two chain bers at the same time andvunder the same,

pressure while the carbon granules on the opposite side of the movable electrodes are s1multaneously loosened or relieved of pressure proportionately to the compression of the granules on the other side of the movable electrodes, and that in the reverse movement of the movable electrodes a corresponding action and coiiperation and release of pressure ensues, so that alternating high and low potentials are produced in the transmitter. This particular arrangement of electrodes in conjunction with the granular carbon increases the efficiency of the transmitter and produces an exceptionally clear and disthe same novel features and advantages. t i

tinct reproduction of wave vibrations which:

is particularlywell adapted for instruments for production and transmission ofzwoice currents, as wellas for transmission of-other wave vibrations.

Having described my invention and set? forth its merits what I claim is:

1. telephone instrument comprising a plurallty of chambers for granular carbon arranged side by side, front and rear electrodes and a movable centrally disposed electrode in each chamber, granular carbon between the several electrodes in each chamber, a diaphragm common to the several chambers and supported to be bodily movable throughout its whol e area, and means for arately connecting the diaphragm to the moi able electrode of each chamber to simultaneously compress granular carbon in both chambers on one side of the movable electrodes while releasing compression on the granular carbon on the other side of both of said electrodes, substantially as described.

2. A telephone instrument comprising a casing having a chambered portion formed with a diaphragm-seat, a diaphra m restin upon said seat, a backing-disk tted over chambers and supported to bebodily mov-' $33? J-WAILAFE? new the diaphragm, means securing the backing diskto its adjustment over the diaphragm, a-plurality of chambers mounted upon the backing-disk and having each front and rear electrodes and a centrally disposed movable electrode, granular carbon, between the several electrodes, andv means extending centrally from the face of each movable electrode directly to the diaphragm and connected therewith at points equidistant from the} periphery of the diaphragm toexert pressure from the diaphragm on the several electrodes in-the direction of line of movement of the electrodes to simultaneously compress ranular carbon in both chambers on one si e of the movable electrodes while releasing, compression on; the other side thereof, substantially: as described.

' 3. A tele hone instrument comprising a plurality of chambers for granular carbon arranged side by side, front and rear electrodes and a movable centrally disposed electrode in each chamber, granular carbon between the several electrodes in each chaniber, a diaphragm common to the several}.

able throughout its whole area, and meansconnecting 'eachmovable electrode to the diaphragm to one side of its center to positively. move the several electrodes to the same extent and simultaneously with eachother correspondingly, to the movement of the diaphragm to compress thegranular .,carbon in each chamber on one side of-the {movable electrodes While releasing compres "s'ion on the granularcarbon on the other sideiof, both electrodes, substantially as de-' scribed;

1 ..-4.- A telephone instrument comprising a granular carbon holding chamber containmg a movable electrode, and a diaphragm connected with the electrode, said diaphra formed of relatively thin material and aving ribsradiating from its center ;;to render it non-flexible in response to vibrations, substantially as described. I p

5. A telephone instrument comprising a plurality of chambers for granular carbon granular earbcn in each 0 amber on one side of the movable electrodes while releasing compression of the granular carbon on the other side thereof, and appropriate electrical. connection to form two independent balanced circuits acting in conjunction to utilize the product of a simultaneous unbalancing in each, and each actuated by the same vibration, substantially as described.

6. A transmitter. comprising a casing chambered and formed with a, diaphragm *seat in the chamber, a'diaphragm cushioned upon said seat so as to be movable to and fro thereon, a backing disposed opposite 'jsai d diaphragm, a granular carbon holding greceptacle mounted upon said backing an ,coinprising a plurality of chamberseach provided with oppositely disposed electrodes and an interposedmovab e electrode,

and means passing through said-backing and connecting the diaphragm and movableelectrodes and adapted to move .the several electrodes to the same extent and simultaneously with each other to compress the granular carbon on one side of the movable "electrodes while releasing compression on the granular carbon on the otherside of the several electrodes, substantiallyas described. In testimony whereof I aflix my signature in presence of iDWO WItDQSSGS.

WILLIAM PRESTON STUNZ. Witnesses:

J. HOOPER EDMONDSON, WM. H. MARTIN.

. copies of this patent may be obtained for five cent: each, by addressing the (lommissloner of Patents,

Washington, D. 0. i 

